10-gear automatic transmission

ABSTRACT

The invention concerns an automatic transmission of planetary structure, comprising a drive input shaft (AN), a drive output shaft (AB), first, second, third and fourth planetary gear sets (RS 1 , RS 2 , RS 3 , RS 4 ) and six shifting element (A, B, C, D, E, F). By the selective engagement of three of a total of six shifting elements (A to F), ten forward gears and up to two reverse gears can be engaged without range shifts.

This application is a divisional of U.S. patent application Ser. No.12/747,755 filed Jun. 11, 2010, which is a National Stage completion ofPCT/EP2008/066975 filed Dec. 8, 2008, which claims priority from Germanpatent application serial no. 10 2007 055 808.4 filed Dec. 14, 2007.

FIELD OF THE INVENTION

The present invention concerns a 10-gear automatic transmission ofplanetary structure, in particular for a motor vehicle.

BACKGROUND OF THE INVENTION

According to the prior art, automatic transmissions, in particular formotor vehicles, comprise planetary gearsets which are shifted by meansof frictional or shifting elements such as clutches and brakes and whichare usually connected with a starting element that can operate with slipand is optionally provided with a bridging clutch, such as ahydrodynamic torque converter or a flow clutch.

Automatically shifted vehicle transmissions of planetary structure ingeneral have been described many times in the prior art and areconstantly undergoing further development and improvement. Suchtransmissions should have a sufficient number of forward gears and areverse gear, and transmission ratios that are very well suited formotor vehicles and have a large overall spread and appropriate stepintervals. Furthermore, they should enable a high starting transmissionratio in the forward direction and should possess a direct gear and besuitable for use both in passenger cars and in utility vehicles. Inaddition these transmissions should entail as little structuralcomplexity and cost as possible, in particular requiring only a smallnumber of shifting elements, and should avoid double shifts forsequential shifting operations so that for shifts in defined gear groupsin each case only one shifting element is changed.

A multi-gear automatic transmission of this type is described, forexample in WO 2006/074707 A1 by the present applicant. It comprisesessentially a drive input shaft and a drive output shaft arrangedcoaxially with one another, a total of four single planetary gearsetsand five frictional shifting elements. By selective engagement in eachcase of three of the five frictional shifting elements made as clutchesand brakes a total of eight forward gears can be engaged without groupshifts, i.e. they can be engaged or disengaged in such manner that onchanging from one gear to the next-higher or next-lower gear, in eachcase only one of the previously engaged shifting elements is disengagedand one previously disengaged shifting element is engaged.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a multi-steptransmission of the type mentioned at the start, with at least tenforward gears that can be engaged without group shifts and at least onereverse gear, in which, using a total of four planetary gearsets, theleast possible number of shifting elements is needed. In addition thetransmission should be characterized by a large spread in relation togear steps acceptable for drivability, and in the main driving gears, bygood efficiency, i.e. comparatively low drag and gearing losses.

According to these, an automatic transmission of planetary structure isproposed according to the invention, which comprises a drive inputshaft, a drive output shaft, four planetary gearsets and only sixshifting elements, namely two brakes and four clutches, whose selectiveengagement gives various transmission ratios between the drive input andthe drive output shafts, such that ten forward gears and at least onereverse gear can be produced. In each gear, three of the total of sixshifting elements are engaged. To change from one gear to thenext-higher or next-lower gear, in each case only one of the previouslyengaged shifting elements is disengaged and one previously disengagedshifting element is engaged.

Preferably, the drive output shaft of the transmission is rigidlyconnected to an element of one of the four planetary gearsets andrigidly connected to the output elements of two of the transmission'sshifting elements, such that one of these two shifting elementsconnected on their output side to the drive output shaft is rigidlyconnected on its input side with another element of this planetarygearset rigidly connected to the drive output shaft.

In an advantageous design the sixth shifting element is suitable forproducing a hill-holder function in the transmission, by virtue ofwhich, with the shifting element engaged at the same time, the driveoutput shaft can be locked in the transmission.

In a preferred embodiment the automatic transmission according to theinvention comprises the following kinematic couplings of the gearsetelements to one another and to the drive input and drive output shafts:

-   -   the fourth planetary gearset is rigidly connected to the drive        input shaft, is connected rigidly in each case by an active        connection to the first and second planetary gearsets, and can        be connected by means of the first shifting element to a housing        of the transmission,    -   the third planetary gearset is rigidly connected to the drive        output shaft, is connected rigidly in each case by an active        connection to the first and second planetary gearsets, and can        be connected by the fourth shifting element to the second        planetary gearset,    -   the second planetary gearset can be blocked by the fifth        shifting element and can be connected by the sixth shifting        element to the first and third planetary gearsets,    -   the first planetary gearset can be connected to the housing by        the first shifting element and by the second shifting element.

By virtue of these various kinematic couplings of the shifting elementsto the various shafts of the automatic transmission, according to theinvention an entire gear family is obtained.

A number of advantageous designs of an automatic transmission of thistype according to the invention are based on the 8-gear automatictransmissions known from WO 2006/074707 A1 with the following kinematiccouplings of the gearset elements to one another: A carrier of thefourth planetary gearset and the drive input shaft are connected in arotationally fixed manner to one another and form the first rotary shaftof the transmission. A carrier of the third planetary gearset and thedrive output shaft are connected in a rotationally fixed manner to oneanother and form the second rotary shaft of the transmission. A sun gearof the first planetary gearset and a sun gear of the fourth planetarygearset are connected in a rotationally fixed manner to one another andform the third rotary shaft of the transmission. A ring gear of thefirst planetary gearset forms the fourth rotary shaft of thetransmission. A ring gear of the second planetary gearset and a sun gearof the third planetary gearset are connected in a rotationally fixedmanner to one another and form the fifth rotary shaft of thetransmission. A carrier of the first planetary gearset and a ring gearof the third planetary gearset are connected in a rotationally fixedmanner to one another and form the sixth rotary shaft of thetransmission. A sun gear of the second planetary gearset and a ring gearof the fourth planetary gearset are connected in a rotationally fixedmanner to one another and form the seventh rotary shaft of thetransmission. A carrier of the second planetary gearset forms the eighthrotary shaft of the transmission. The above gearset kinematic system isidentical to the gearset kinematic system of the 8-gear automatictransmission known from WO 2006/074707 A1.

With regard to the connection of the six shifting elements to thevarious elements of the planetary gearsets and to the drive input shaftin this preferred embodiment of an automatic transmission according tothe invention, it is provided that the first shifting element isarranged in the force flow between the third shaft and a housing of thetransmission, the second shifting element in the force flow between thefourth shaft and the housing of the transmission, and the third shiftingelement in the force flow between the fifth and the first shaft. Inaddition the fourth shifting element is arranged in the force flowbetween the eighth and the first shaft and that the fifth shiftingelement is arranged in the force flow either between the seventh and thefifth shaft or between the seventh and the eighth shaft or between thefifth and the eighth shaft. The sixth shifting element according to theinvention, which is an additional one compared with WO 2006/074707 A1,is arranged in the force flow between the sixth and the eighth shafts.By virtue of the various kinematic couplings of the fifth shiftingelement to the various shafts of the automatic transmission, here too agear family is obtained.

The shifting or gear logic of this advantageous automatic gear familyaccording to the invention is as follows: In the first forward gear thefirst, second and third shifting elements are engaged and transmittorque. In the second forward gear the first, second and fifth shiftingelements are engaged and transmit torque. In the third forward gear thesecond, third and fifth shifting elements are engaged and transmittorque. In the fourth forward gear the second, fourth and fifth shiftingelements are engaged and transmit torque. In the fifth forward gear thesecond, third and fourth shifting elements are engaged and transmittorque. In the sixth forward gear the second, third and sixth shiftingelements are engaged and transmit torque. In the seventh forward gearthe third, fifth and sixth shifting elements are engaged and transmittorque. In the eighth forward gear the first, third and sixth shiftingelements are engaged and transmit torque. In the ninth forward gear thefirst, third and fourth shifting elements are engaged and transmittorque. In the tenth forward gear the first, fourth and fifth shiftingelements are engaged and transmit torque. A reverse gear is obtained byengaging the first, second and fourth shifting elements or by engagingthe first, second and sixth shifting elements.

In contrast to the 8-gear automatic transmission known from WO2006/074707 A1, because of the sixth shifting element, which isadditional in comparison with WO 2006/074707 A1, the automatic gearfamily according to the invention now has a hill-holder function in thetransmission: if the first, second, fourth and sixth shifting elementsare all engaged at the same time, the drive output shaft of theautomatic transmission is fixed or blocked relative to the transmissionhousing.

All four of the planetary gearsets are preferably designed as so-termednegative planetary gearsets, whose respective planetary gears mesh withthe sun gear and the ring gear of the planetary gearset concerned. Withregard to the spatial arrangement of the four planetary gearsets in thehousing of the automatic transmission, in one design version it isproposed to arrange all four of the planetary gearsets coaxially andnext to one another in the defined sequence “first, fourth, second andthird planetary gearset”, which makes it possible for all four of theplanetary gearsets each to have at most one shaft of the transmissionpassing centrally through it. For an application with the drive inputand drive output shafts extending coaxially with one another, it isappropriate in this case for the first planetary gearset to be thatplanetary gearset of the planetary gearset group which faces toward thedrive input of the automatic transmission. In another design, withregard to the spatial arrangement of the four planetary gearsets in thehousing of the automatic transmission, it is proposed to arrange allfour planetary gearsets coaxially and next to one another in the definedsequence “second, fourth, first and third planetary gearset”. A morecompact transmission structure is obtained with this design inparticular if, viewed spatially, the fourth and sixth shifting elementsare arranged in an area axially between the first and third planetarygearsets. For an application with the drive input and drive outputshafts positioned coaxially with one another, in this case it isappropriate for the second planetary gearset to be that planetarygearset of the planetary gearset group which faces toward the driveinput of the automatic transmission.

Particularly for passenger automobiles, all the proposed embodiments anddesigns for a 10-gear automatic transmission according to the inventionhave suitable transmission ratios with a very large overall spread inrelation to the gear steps acceptable for drivability, and this resultsin a significant reduction of fuel consumption. Furthermore, the 10-gearautomatic transmission according to the invention is characterized by anextraordinarily small number of shifting elements for the number ofgears—namely two brakes and four clutches—and comparatively littlestructural complexity. In addition, with the 10-gear automatictransmission according to the invention the efficiency is high in allthe gears, because of low drag losses since in every gear three of thesix shifting elements are engaged, and due to low gearing losses in thesimply constructed single planetary gearsets.

Advantageously, with the 10-gear automatic transmission according to theinvention the motor vehicle can be started both by means of a startingelement external to the transmission and with a transmission-internalfrictional shifting element. In a manner known per se, atransmission-external starting element can for example be in the form ofa hydrodynamic converter, a so-termed dry starting clutch, a so-termedwet starting clutch, a magnetic powder clutch, or a centrifugal forceclutch. Alternatively to arranging such a starting element in the forceflow direction between the drive engine and the transmission, thetransmission-external starting element can also be positioned in theforce flow direction behind the transmission and in that case thetransmission input shaft is connected in a rotationally fixed manner orwith some rotational elasticity, to the crankshaft of the drive engine.Particularly suitable as a transmission-internal starting element is oneof the two brakes, which is actuated in the first and second forwardgears and in the reverse gear.

Furthermore, the 10-gear automatic transmission according to theinvention is designed to be adaptable to various drivetrain designs,both in the force flow direction and in relation to the space available.Thus, with the same transmission layout, depending on the fixedtransmission ratio of the individual planetary gearsets different gearintervals can be obtained, so enabling application-specific orvehicle-specific variation. Moreover, without special design measuresthe drive input and drive output of the transmission can optionally bearranged coaxially or axis-parallel to one another. An axle differentialand/or a distributor differential can be arranged on the drive inputside or the drive output side of the transmission. It is also possibleto provide additional freewheels at any suitable points of themulti-step transmission, for example between a shaft and the housing orif necessary to connect two shafts. In addition a wear-free brake suchas a hydraulic or electrical retarder or suchlike can be arranged on anyshaft, preferably on the drive input or the drive output shaft, and thisis especially important particularly for use in utility vehicles.Furthermore, for powering additional aggregates, an auxiliary driveoutput can be provided on any shaft, preferably on the drive input orthe drive output shaft. Another advantage of the automatic transmissionaccording to the invention is that an electric machine can also becoupled to any shaft as a generator and/or as an additional drive motor.

The shifting elements used can be in the form of shift-under-loadclutches or brakes. In particular frictional clutches or brakes such asdisk clutches, belt brakes and/or conical clutches can be used. However,interlocking brakes and/or clutches such as synchronizers or claw brakescan also be used as shifting elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, examples of the invention are explained in more detail withreference to the drawings, in which the same or comparable componentsare identified by the same indexes and which show:

FIG. 1. Schematic representation of a first example embodiment of a10-gear automatic transmission according to the invention

FIG. 2. Illustration of a shifting scheme for the transmission shown inFIG. 1

FIG. 3. Illustration showing a first component configuration variant forthe transmission of FIG. 1, represented schematically

FIG. 4: Illustration showing a second component configuration variantfor the transmission of FIG. 1

FIG. 5: Illustration showing a third component configuration variant forthe transmission of FIG. 1

FIG. 6: Illustration showing a fourth component configuration variantfor the transmission of FIG. 1

FIG. 7: Illustration showing a fifth component configuration variant forthe transmission of FIG. 1

FIG. 8: Illustration showing a sixth component configuration variant forthe transmission of FIG. 1

FIG. 9: Illustration showing a seventh component configuration variantfor the transmission of FIG. 1

FIG. 10: Illustration showing an eighth component configuration variantfor the transmission of FIG. 1

FIG. 11: Illustration showing a ninth component configuration variantfor the transmission of FIG. 1

FIG. 12: Illustration showing a tenth component configuration variantfor the transmission of FIG. 1, schematically represented

FIG. 13: Schematic representation of a second example embodiment of a10-gear automatic transmission according to the invention; and

FIG. 14: Schematic representation of a third example embodiment of a10-gear automatic transmission according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a simplified, schematic representation of a first exampleembodiment of a 10-gear automatic transmission according to theinvention. The transmission comprises a drive input shaft AN, a driveoutput shaft AB, four planetary gearsets RS1, RS2, RS3, RS4 and sixshifting elements A, B, C, D, E, F, all arranged in a housing GG of thetransmission. All four of the planetary gearsets RS1, RS2, RS3, RS4 areformed as simple negative planetary gearsets. As is known, a negativeplanetary gearset has planetary gears that mesh with the sun gear andthe ring gear of the planetary gearset. The ring gears of the fourplanetary gearsets RS1, RS2, RS3, RS4 are indexed HO1, HO2, HO3 and HO4,their sun gears SO1, SO2, SO3 and SO4, the planetary gears PL1, PL2,PL3, and PL4, and the carriers on which the planetary gears are mountedto rotate are indexed ST1, ST2, ST3 and ST4. The automatic transmissionaccording to the invention comprises a total of eight rotary shaftsindexed from 1 to 8.

The shifting elements A and B are in the form of brakes which, in theexample embodiment shown, are both frictional shifting disk brakes butwhich, in other designs, could also be made as frictional shifting beltbrakes or for example even as interlock-type shifting claw or conebrakes. The shifting elements C, D, E and F are clutches which, in theexample embodiment shown, are all made as frictional shifting diskclutches but which, in another design, could for example also beinterlock-type shifting claw or cone clutches. With this total of sixshifting elements A to F, selective engagement of ten forward gears andup to two reverse gears can be obtained, as will be explained in moredetail later with reference to FIG. 2.

As regards the coupling of the individual elements of the four planetarygearsets RS1, RS2, RS3, RS4 to one another and to the drive input anddrive output shafts AN, AB, the following provisions are made in theautomatic transmission according to FIG. 1: The carrier ST4 of thefourth planetary gearset RS4 and the drive input shaft AN are connectedin a rotationally fixed manner to one another and form the first shaftof the automatic transmission, indexed 1. The carrier ST3 of the thirdplanetary gearset RS3 and the drive output shaft AB are connected in arotationally fixed manner to one another and form the second shaft ofthe automatic transmission, indexed 2. The sun gear SO1 of the firstplanetary gearset RS1 and the sun gear SO4 of the fourth planetarygearset RS4 are connected in a rotationally fixed manner to one anotherand form the third shaft of the automatic transmission, indexed 3. Thering gear HO1 of the first planetary gearset RS1 forms the fourth shaftof the automatic transmission, indexed 4. The ring gear HO2 of thesecond planetary gearset RS2 and the sun gear SO3 of the third planetarygearset RS3 are connected in a rotationally fixed manner to one anotherand form the fifth shaft of the automatic transmission, indexed 5. Thecarrier ST1 of the first planetary gearset RS1 and the ring gear HO3 ofthird planetary gearset RS3 are connected in a rotationally fixed mannerto one another and form the sixth shaft of the automatic transmission,indexed 6. The sun gear SO2 of the second planetary gearset RS2 and thering gear HO4 of the fourth planetary gearset RS4 are connected in arotationally fixed manner to one another and form the seventh shaft ofthe automatic transmission, indexed 7. The carrier ST2 of the secondplanetary gearset forms the eighth shaft of the automatic transmission,indexed 8.

As regards the coupling of the six shifting elements A to F to theabove-described shafts 1 to 8 of the transmission, in the automatictransmission according to the invention shown in FIG. 1 the followingprovisions are made: The first shifting element A is arranged in theforce flow between the third shaft 3 and the transmission housing GG.The second shifting element B is arranged in the force flow between thefourth shaft 4 and the transmission housing GG. The third shiftingelement C is arranged in the force flow between the fifth shaft 5 andthe first shaft 1. The fourth shifting element D is arranged in theforce flow between the eighth shaft 8 and the second shaft 2. The fifthshifting element E is arranged in the force flow between the seventhshaft 7 and the fifth shaft 5. Finally, the sixth shifting element F isarranged in the force flow between the sixth shaft 6 and the eighthshaft 8.

In the example embodiment shown in FIG. 1 the four planetary gearsetsRS1, RS2, RS3, RS4, as viewed in the axial direction, are arrangedcoaxially one after another in the defined sequence “RS1, RS4, RS2,RS3”, with the drive input shaft AN and drive output shaft AB arrangedcoaxially with one another, the first planetary gearset RS1 being thegearset of the automatic transmission closest to the drive input and thethird planetary gearset RS3 being the gearset of the automatictransmission closest to the drive output. In an advantageous manner thisarrangement is such that only one shaft of the automatic transmissionpasses centrally in the axial direction through each of the fourplanetary gearsets RS1, RS2, RS3 and RS4.

In principle, the shifting elements of an automatic transmissionaccording to the invention can be spatially arranged inside thetransmission in any desired way, limited only by the dimensions andexternal shape of the transmission housing GG. Correspondingly, thecomponent configuration shown in FIG. 1 is expressly to be understood asonly one of many possible component configuration variants. Those withknowledge of the field will find numerous suggestions, for example inthe already-mentioned WO 2006/074707 A1. The example embodiment shown inFIG. 1, on account of its slim housing structure, is well situated forfitting into a motor vehicle with a so-termed “standard drive”. Thecomponent configuration shown in FIG. 1 is based on the automatictransmission shown in FIG. 4 of WO 2006/074707 A1 and differs from itonly in the connection and arrangement of the clutch F which—as alreadymentioned—is additional compared with WO 2006/074707 A1.

As can be seen in FIG. 1, the two planetary gearsets RS1 and RS4 aredirectly adjacent. In the example embodiment shown, as viewed spatiallythe two brakes A, B are arranged axially next to one another in an areaabove the planetary gearset RS1 in this case close to the drive input,the brake B being arranged, at least partially, radially above the firstplanetary gearset RS1. Here, for example, the diameters of the disk setsof these two brakes A, B are at least similar. In a simply designedmanner the brake A can also be integrated in a housing wall of thetransmission housing GG close to the drive input. As already indicated,the spatial arrangement of the two brakes A, B is to be understood onlyas an example. Thus, to make the axial length of the transmissionshorter, in another design it could for example be provided that whilethe disk sets remain axially adjacent the brake A is positioned at leastpartially in an area radially over the first planetary gearset RS1 andthe brake B at least partially in an area radially over the fourthplanetary gearset RS4. In yet another design it could for example beprovided that the two brakes A, B are not positioned axially adjacent,but partially or completely radially one above the other.

As can also been seen from FIG. 1, as viewed spatially, the threeclutches C, D and E are arranged in an area axially between the secondplanetary gearset RS2 close to the fourth planetary gearset RS4, and thethird planetary gearset RS3 close to the drive output. On the side ofthe second planetary gearset RS2 facing toward the third planetarygearset RS3 the clutch E is directly adjacent to the second planetarygearset RS2. Viewed spatially, the disk set of the clutch D ispositioned approximately radially over the disk set of the clutch C, sothat the two clutches C and D are axially adjacent to the thirdplanetary gearset RS3 (on the side thereof that faces toward the secondplanetary gearset RS2). In this case the shaft 5, which forms the activeconnection between the ring gear HO2 of the second planetary gearset RS2and the sun gear SO3 of the third planetary gearset RS3, completelyencloses the clutch F in the axial direction so that the clutch E isinside a cylindrical space formed by the shaft 5. Moreover the shaft 8,which forms the active connection between the carrier ST2 of the secondplanetary gearset RS2 and the clutch D, completely encloses the secondplanetary gearset RS2 and the clutch E in the axial direction. Thus theclutch E too is inside a cylindrical space formed by the shaft 8. Asalready indicated, the spatial arrangement of the three clutches C, Dand E shown in FIG. 1 is to be understood only as an example. Thus,depending on the fitting space available in the vehicle for installingthe transmission, it may be expedient to position the disk set of theclutch D approximately radially over the disk set of the clutch E. Inanother design the clutch C could for example be arranged axiallybetween the clutch E close to RS2 and the clutch D close to RS3, and insuch a case the disk sets of the three clutches E, C and D wouldpreferably be arranged on an at least similar and large diameter,whereby the resulting comparatively large axial extension of this clutcharrangement would not be disadvantageous for a “standard drive” becauseof the customary cardan tunnel contour of the vehicle.

As already mentioned, only one shaft of the transmission passescentrally through each of the four planetary gearsets RS1 to RS4 in theaxial direction. To be specific, only the drive input shaft AN or theshaft 1 passes centrally completely through the planetary gearsets RS1,RS4 and RS2 in the axial direction, such that along its axial course thedrive input shaft AN passes centrally through the third shaft 3, theseventh shaft 7 and part of the fifth shaft 5. This is particularlyadvantageous, on the one hand for the dimensioning of the drive inputshaft AN and the gearsets, but on the other hand also because it entailsa comparatively simple lubricant supply to the planetary gears of thefour planetary gearsets RS1 to RS4 and also entails a comparativelysimple supply of pressure and lubricant to the three clutches E, D, C.

As can also be seen from FIG. 1, along its axial course the shaft 6 ofthe transmission, which indeed forms the active connection between thecarrier ST1 of the first planetary gearset RS1 and the ring gear HO3 ofthe third planetary gearset RS3, encloses the fourth and secondplanetary gearsets RS4, RS2 and the two clutches E, D completely, and soforms the cylindrical space within which the disk set of the clutch Fand the servomechanism of the clutch F for actuating the disk set areaccommodated. As already mentioned, this clutch F is not present in thetype-defining WO 2006/074707 A1. In the example embodiment shown in FIG.1 the disk set of the clutch F, viewed spatially, is arranged in an areaaxially between the fourth planetary gearset RS4 and the secondplanetary gearset RS2, on a diameter radially above the planetarygearsets RS4, RS2. In accordance with the kinematic connection of theclutch F to the sixth shaft 6 and the eighth shaft 8 of thetransmission, and with the spatial position of the shaft 8 centrallyinside the shaft 6, in this case a section of the shaft 6 forms theouter disk carrier and a section of the shaft 8 the inner disk carrierof the clutch F. From this it can also be seen that a person withknowledge of the field has some freedom in the positioning of the diskset of the clutch F as viewed in the axial direction. Thus, in a designdiffering from FIG. 1 it could for example be provided that the disk setof the clutch F is arranged in an area radially over the fourthplanetary gearset RS4 or in an area radially over the second planetarygearset RS2 and the third planetary gearset RS3—radially over the clutchassembly C/D/E and/or close to the planetary gearset RS3. Theservomechanism associated with the disk set of the clutch F can bearranged both on the side of the disk set of the clutch F that facestoward the first planetary gearset RS1 and also on the side of the diskset of the clutch F that faces toward the third planetary gearset RS3.Examples of this will be explained in more detail later with referenceto the other figures.

FIG. 2 shows an example of a shifting scheme for the 10-gear automatictransmission according to the invention in FIG. 1. In each gear threeshifting elements are engaged and three are disengaged. Besides theshifting logic, example values for the respective transmission ratios iof the individual gear steps and the gear intervals φ to be determinedtherefrom can also be obtained from the shifting scheme. Thetransmission ratios i indicated are obtained from the (typical) fixedtransmission ratios of the four planetary gearsets RS1, RS2, RS3, RS4 ofminus 2.0, minus 1.60, minus 3.70 and minus 2.00. Furthermore, it can beseen from the shifting scheme that in sequential shift operations doubleshifts or group shifts are avoided, since two gear steps adjacent in theshift logic always use two shifting elements common to both. The seventhforward gear is made as a direct gear.

The first forward gear is obtained by engaging the brakes A and B andthe clutch C, the second forward gear by engaging the brakes A and B andthe clutch E, the third forward gear by engaging the brake B and theclutches C and E, the fourth forward gear by engaging the brake B andthe clutches D and E, the fifth forward gear by engaging the brake B andthe clutches C and D, the sixth forward gear by engaging the brake B andthe clutches C and F, the seventh forward gear by engaging the clutchesC, E and F, the eighth forward gear by engaging the brake A and theclutches C and F, the ninth forward gear by engaging the brake A and theclutches C and D, and the tenth forward gear by engaging the brake A andthe clutches D and E. As can also be seen from the shifting scheme, afirst reverse gear is obtained by engaging the brakes A and B and theclutch D. A second reverse gear is obtained by engaging the brakes A andB and the clutch F.

According to the invention the motor vehicle can be started by means ofa shifting element integrated in the transmission. For this aparticularly suitable shifting element is one which is needed both inthe first forward gear and in the reverse gear, i.e. in this casepreferably the brake A or the brake B. Advantageously, these two brakesare also needed in the second forward gear. If the brake B is used asthe starting element integrated in the transmission, then starting iseven possible in any of the first five gears and in the two reversegears. As can be seen from the shifting scheme, as effectivetransmission-internal starting elements the clutch C is also suitablefor starting in the forward direction and the clutch D for starting inthe reverse direction.

A hill-holder function in the transmission, in which the drive outputshaft AB of the transmission is held fixed relative to the transmissionhousing GG, is obtained by simultaneously engaging the brakes A and Band the clutches D and F. Starting in the first forward gear from apreviously activated hill-holder function can be carried out by means ofa simple overlap shift in which the clutch C is engaged while at thesame time the clutches D and F are disengaged. Starting in the secondforward gear from a previously activated hill-holder function can alsobe carried out by a simple overlap shift in which the clutch E isengaged and the clutches D and F are simultaneously disengaged. It isparticularly simple to start in the first reverse gear from a previouslyactivated hill-holder function, since to do this all that is necessaryis to disengaged the clutch F. Likewise, it is simple to start in thesecond reverse gear from a previously activated hill-holder function,since for this it is only necessary to disengaged the clutch D.

In principle the spatial arrangement of the shifting elements within thetransmission in the example embodiment of a 10-gear automatictransmission according to the invention shown in FIG. 1, can be asdesired and is limited essentially only by the dimensions and externalshape of the transmission housing GG. Correspondingly, FIGS. 3 to 11show various examples of appropriate component configuration variantsfor the 10-gear automatic transmission according to FIG. 1, in each casewith kinematic coupling of the gearset elements, shifting elements andshafts unchanged compared with FIG. 1. Furthermore, in the componentconfiguration variants shown in FIGS. 3 to 11, the four planetarygearsets RS1 to RS4, viewed in the axial direction, are arrangedcoaxially one behind another in the sequence “RS1, RS4, RS2, RS3” as inFIG. 1.

FIG. 3 now shows a first example component configuration variant for thetransmission in FIG. 1, again represented in simplified schematic form.Different than FIG. 1 the drive input AN and drive output AB shafts arethis time not arranged coaxially, so that this first componentconfiguration variant is particularly suitable for a vehicle withso-termed front transverse drive, with the transmission output arrangedaxis-parallel to the transmission input. A further difference from FIG.1 is that the drive input of the transmission is this time, for example,arranged on the side of the transmission opposite to the first planetarygearset RS1. This is possible because the drive input shaft AN or thefirst shaft 1 of the transmission can pass centrally through thetransmission over its full axial length. Different than FIG. 1, in thetransmission according to FIG. 3 the third shifting element C is notarranged on the side of the third planetary gearset RS3 facing towardthe second planetary gearset RS2, but this time on the side of the thirdplanetary gearset RS3 facing away from the second planetary gearset RS2.In this case the drive output shaft AB runs—for example in the manner ofa spur drive—at least in part axially between the planetary gearset RS3and the clutch C. For the arrangement of the clutch C this configurationmakes available a larger diameter in the area between the drive outputspur gear connected to the carrier ST3 and outer wall GW of thehousing—here for example on the drive input side. Another differencebetween the transmissions according to FIGS. 1 and 3 is that in FIG. 3the clutch F—or at least its disk set—as viewed spatially is arrangedradially over the clutch D and axially next to the third planetarygearset RS3, whereby a common disk carrier can be used for the twoclutches D and E, which then forms the inner disk carrier for the clutchF and the outer disk carrier for the clutch D.

With reference to FIGS. 4 to 11 further example embodiments of a 10-gearautomatic transmission according to the invention are described below,these being based on the transmission shown in FIG. 1 with its coaxialdrive input and output, with the particular intention of indicatingvarious appropriate possibilities for the spatial arrangement of thedisk sets of the six frictional shifting elements and theservomechanisms associated with the disk sets. In addition to theindexes already mentioned, in all of FIGS. 4 to 11 the followingsupplementary nomenclature is used: the outer disk carriers of the sixshifting elements A to F are denoted A_a to F_a, the inner disk carriersof the six shifting elements A to F are denoted A_i to F_i, the disksets of the six shifting elements A to F are denoted A_l to F_l and theservomechanisms for actuating these disk sets A_l to F_l are denoted A_sto F_s. A servomechanism of this type usually comprises at least onehydraulically or pneumatically actuated piston that acts upon itsassociated disk set, a pressure space that acts upon the piston and canbe filled with pressure medium for the purpose of engaging the disk set,and a piston restoring element such as a spring or a restoring pressurechamber for the purpose of disengaging the disk set. If the shiftingelement is a clutch, then the servomechanism associated with the clutchusually also comprises a means for compensating the rotary pressure ofthe pressure space filled with pressure medium, usually comprising apressure compensation space that can be filled with lubricant not underpressure and which acts upon the piston in opposition to its engagingdirection. In other respects, for those with knowledge of the field therepresentations shown in FIGS. 4 to 11 are self-explanatory.

FIG. 4, then, shows an example second component configuration variantfor the transmission of FIG. 1. In contrast to FIG. 1 the third shiftingelement C, viewed spatially, is now arranged axially completely betweenthe fourth and second planetary gearsets RS4, RS2. The fourth, fifth andsecond shifting elements D, E, F, viewed spatially, are arranged axiallycompletely between the second and third planetary gearsets RS2, RS3, thefifth shifting element E being axially directly adjacent to the secondplanetary gearset RS2 and the fourth and sixth shifting elements D, Fforming an assembly which is axially directly adjacent to the thirdplanetary gearset RS3. Thus, the assembly comprises a common diskcarrier which forms a section of the shaft 8 and is connected to thecarrier ST2 of the second planetary gearset RS2. This common diskcarrier is the outer disk carrier D_a for the clutch D and the innerdisk carrier F_i for the clutch F,

Furthermore, the assembly of shifting elements D, F contains the diskset D_l of the clutch D arranged inside the cylindrical space of thecommon disk carrier D_a/F_i, the disk set F_l of the clutch F arrangedradially over the disk set D_a/F_i, the disk set F_l of the clutch Farranged radially over the disk set D_l, the servomechanism D_s foractuating the disk set D_l of the clutch D, and the servomechanism F_sfor actuating the disk set F_l of the clutch F. A special design featurein this case is that the servomechanism D_s is arranged inside thecylindrical space of the common disk carrier D_a/F_i, the servomechanismF_s partially coaxially encloses the common disk carrier D_a/F_i, andboth servomechanisms Ds, F_s are mounted so that they can move axiallyon the common disk carrier D_a/F_i, being arranged axially substantiallynext to one another and separated from one another only by a wall of theinner disk carrier D_i. Thus, the two servomechanisms D_s, F_s act ineach case on the side of the associated disk set D_l or F_l that facestoward the third planetary gearset RS3 and, to engage the respectiveclutch D or F, they actuate the associated disk set D_l or F_l axiallyin the direction opposite to the third planetary gearset RS3, i.e.axially in the direction of the second planetary gearset RS2. Bothservomechanisms D_s, F_s always rotate at the speed of the shaft 8, i.e.always at the same speed as the carrier ST2 of the second planetarygearset RS2 and the drive output shaft AB.

The inner disk carrier D_i of the clutch D forms a section of the shaft2 and in accordance with the transmission layout is connected via thecarrier ST3 of the third planetary gearset RS3, in this case close tothe drive output, to the drive output shaft AB. The section of the shaft6 close to the ring gear HO3 of the third planetary gearset RS3 formsthe outer disk carrier F_a of the sixth shifting element F, and inaccordance with the transmission layout the outer disk carrier F_a isconnected on its side facing away from the third planetary gearset RS3to the carrier ST1 of the first planetary gearset RS1 which in this caseis close to the drive input.

A further difference between the transmissions according to FIG. 1 andFIG. 4 is that in FIG. 4 the first shifting element A, made as a brake,is arranged on a smaller diameter than the second shifting element Balso made as a brake, whereby in the area radially over the disk set A_lof the brake A and on the side close to the drive input axially adjacentto the disk set B_l of the brake B some structural space is providedwithin the inside space of the transmission, which is particularly wellsuited for accommodating a hydraulic pump of the transmission positionedaxis-parallel to the drive input shaft AN (not shown in FIG. 4 for thesake of simplicity).

FIG. 5 shows an example third component configuration variant for thetransmission according to FIG. 1. Different than FIG. 1, in FIG. 5 it isnow provided that, viewed spatially, the brake A is arranged largelyradially under the brake B, the clutches E, C and D are arranged in thatorder axially next to one another with disk sets E_l, C_l, and D_l ofthe same or at least approximately the same diameter, and the clutch Fdirectly adjacent to the third planetary gearset RS3 on its side facingtoward the second planetary gearset RS2. For the two clutches E and C acommon disk carrier is provided, which forms the outer disk carriersE_a, C_a both for the clutch E and for the clutch C. In this case thedesigns of the two clutches E and C are similar.

The design of the two clutches D and F as an assembly is derived fromFIG. 4. Different than that in figure, in FIG. 5 it is provided thatonly the servomechanism F_s of the radially outer clutch F is mounted tomove axially on the disk carrier D_a/F_i common to the two clutches Dand F, and always rotates at the same speed as the shaft 8, while incontrast the servomechanism D_s of the radially inner clutch D ismounted to move axially on the inner disk carrier D_i of the clutch Dand always rotates at the same speed as the shaft 2. In accordance withthis design the assembly D/F of the two clutches D, F should also beregarded as the inner disk carrier D_i.

FIG. 6 shows an example fourth component configuration variant of thetransmission of FIG. 1, based on the third component configurationvariant shown in FIG. 5. The third and fourth component configurationvariants differ only as regards the design and spatial arrangement ofthe servomechanism F_s of the clutch F. In contrast to FIG. 5, this timethe servomechanism F_s according to FIG. 6 always rotates at the speedof the eighth shaft 8 of the transmission, i.e. always at the same speedas the inner disk carrier F_i of the clutch F. For this it is providedthat the servomechanism F_s, viewed spatially, is arranged largely in anarea axially between the fourth and second planetary gearsets RS4, RS2,such that at least the pressure space of this servomechanism F_s ispositioned close to the carrier ST2 of the second planetary gearset RS2,the piston of the servomechanism F_s is mounted to move axially on thiscarrier ST2 or on the inner disk carrier F_i of the clutch F, and anactuating finger of this piston that acts upon the disk set F_l of theclutch F spans radially across the planetary gearset RS2 and theclutches E and C in the axial direction. When the clutch F is beingengaged the piston or the actuating finger of the servomechanism F_sactuates the disk set F_1 axially in the direction of the thirdplanetary gearset RS3.

FIG. 7 shows an example fifth component configuration variant for thetransmission according to FIG. 1, again based on the third componentconfiguration variant shown in FIG. 5. The third and fifth componentconfiguration variants differ only as regards the design and spatialarrangement of the servomechanism F_s of the clutch F. In contrast toFIG. 5, the servomechanism F_s in FIG. 7 this time always rotates at thespeed of the sixth shaft 6 of the transmission, i.e. always at the samespeed as the outer disk carrier F_a of the clutch F. For this it isprovided that the servomechanism F_s, viewed spatially, is arrangedlargely in an area axially between the first and fourth planetarygearsets RS1, RS4, such that at least the pressure space of thisservomechanism F_s is positioned close to the carrier ST1 of the firstplanetary gearset RS1, the piston of the servomechanism F_s is mountedto move axially on this carrier ST1 or on the outer disk carrier F_a ofthe clutch F, and an actuating finger of this piston which acts upon thedisk set F_l of the clutch F spans radially across the planetarygearsets RS4 and RS2 and the clutches E and C in the axial direction.When the clutch F is being engaged, the piston or the actuating fingerof the servomechanism F_s actuates the disk set F_l axially in thedirection of the third planetary gearset RS3.

FIG. 8 shows an example sixth component configuration variant of thetransmission according to FIG. 1, which is based on the fifth componentconfiguration variant shown in FIG. 7. This sixth componentconfiguration variant differs from the fifth component configurationvariant particularly in that according to FIG. 8 the disk set F_l of theclutch F, viewed spatially, is this time positioned in an area radiallyover the planetary gearsets RS2 and RS4 arranged axially directly nextto one another and thus at least partially radially over the fourthplanetary gearset RS4. For this, a section of the eighth shaft 8 of thetransmission which starts from the carrier ST2 of the second planetarygearset RS2 and is formed as the inner disk carrier F_i for the clutch Fextends axially in the direction of the first planetary gearset RS1,which is positioned on the side of the fourth planetary gearset RS4facing away from the second planetary gearset RS2 (and toward the driveinput). Correspondingly, an axial section of the sixth shaft 6 of thetransmission arranged in the area radially over the planetary gearsetRS4 is made as the outer disk carrier F_a for the clutch F. Theservomechanism F_s of the clutch F is positioned essentially axiallybetween the planetary gearsets RS1 and RS4, always rotates at the speedof the carrier ST1 of the first planetary gearset RS1, and when theclutch F is being engaged, actuates the disk set F_l associated with itaxially in the direction of the second and third planetary gearsets RS2,RS3.

A further difference between the transmissions in FIG. 7 and FIG. 8 isthat in FIG. 8 the inner disk carrier D_i of the clutch D is connectedto the eighth shaft 8 of the transmission. Correspondingly, in FIG. 8the outer disk carrier D_a of the clutch D is connected to the secondshaft 2 or drive output shaft AB. This outer disk carrier D_a, formed asa cylinder, besides the disk set DI of the clutch D, also holds theservomechanism D_s of the clutch D provided for actuating the disk setD_l, which can move axially. This makes for a comparatively more simpledesign of the clutch D.

FIG. 9 shows an example seventh component configuration variant of thetransmission according to FIG. 1, based on the sixth componentconfiguration variant shown in FIG. 8. Different than the sixthcomponent configuration variant, in this seventh component configurationvariant it is provided that the disk set F_l of the clutch F, viewedspatially, is arranged in an area medially over the second planetarygearset RS2 and the servomechanism F_s of the clutch F provided foractuating the disk set F_l, as viewed spatially, is arranged largelyaxially between the fourth planetary gearset RS4 and the secondplanetary gearset RS2. Thus the servomechanism F_s always rotates at thespeed of the eighth shaft 8 of the transmission, i.e. at the same speedas the carrier ST2 of the second planetary gearset RS2 and the samespeed as the inner disk carrier F_i of the clutch F. The servomechanismF_s is mounted and able to move axially on the carrier ST2 or on theinner disk carrier F_i, and when the clutch F is being engaged itactuates its associated disk set F_l axially in the direction of thethird planetary gearset RS3.

FIG. 10 shows an example eighth component configuration variant for thetransmission of FIG. 1. The essential characteristic of this eighthcomponent configuration variant is that all four of the clutches C to F,viewed spatially, are arranged at least nearly completely in the areaaxially between the two planetary gearsets RS2 and RS3, with thefollowing design features:

the clutches C and E are arranged axially next to one another and form astructural assembly;

the disk sets D_l and F_l of the clutches D and F are arranged axiallynext to one another and radially over the disk sets C_l and E_l of theclutches C and E;

the disk sets E_l and F_l are arranged close to the planetary gearsetRS2;

the disk set F_l is arranged essentially radially over the disk set C_l;

a common disk carrier is provided for the clutches C and E, which formsa section of the shaft 5 of the transmission, formed as the outer diskcarrier for the two clutches C, E and their disk sets C_l, E_l, andwhich accommodates in an axially movable manner the servomechanisms C_s,E_s of the two clutches C, E provided for actuating the disk sets C_l,E_l so that the two servomechanisms C_s, E_s always rotate at the speedof the shaft 5;

the two servomechanisms C_s, E_s are arranged axially directly next toone another and thus at least partially axially between the two disksets C_l, E_l, and are separated from one another only by an outersurface of the common outer disk carrier C_a, E_a of the clutches C, E,so that when the clutch C is being engaged the servomechanism C_sactuates its associated disk set C_l axially in the direction of thethird planetary gearset RS3, and so that when the clutch E is beingengaged the servomechanism E_s actuates its associated disk set E_laxially in the direction of the second planetary gearset RS2;

a common disk carrier is provided for the clutches D and F, which formsa section of the shaft 8 of the transmission, is formed as the innerdisk carrier D_i, F_i for the two clutches D, F and their disk sets D_l,F_l, and accommodates axially movably the servomechanisms D_s, F_s ofthe two clutches D, F provided for actuating the disk sets D_l, F_l sothat the two servomechanisms D_s, F_s always rotate at the speed of theshaft 8;

when the clutch D is being engaged, the servomechanism D_s actuates thedisk set D_l associated with it axially in the direction of the secondplanetary gearset RS2;

when the clutch F is being engaged, the servomechanism F_s of the clutchF also actuates the disk set F_l associated with it axially in thedirection of the second planetary gearset RS2, and a section oractuating finger of the piston of the servomechanism F_s of the clutch Fthat can be acted on by pressure, which acts upon the disk set F_l,passes through the inner disks of the disk set D_l of the clutch Dmounted on the common inner disk carrier D_i/F_i for the clutches D andF in the axial direction;

-   -   a cylindrical outer disk carrier D_a is provided for the clutch        D, which forms a section of the shaft 2 of the transmission and        is connected by the carrier ST3 of the third planetary gearset        RS3 to the drive output shaft AB;    -   a cylindrical outer disk carrier F_a is provided for the clutch        F, which forms an axial section of the shaft 6, which holds the        outer disks of the disk set F_l of the clutch F, and which,        along its axial length, coaxially encloses the fourth planetary        gearset RS4 and the common inner disk carrier D_i/F_i for the        clutches D and F and the outer disk carrier D_a of the clutch D.

FIG. 11 shows an example ninth component configuration variant for thetransmission according to FIG. 1, which is based on the second componentconfiguration variant shown in FIG. 4. In contrast to the secondcomponent configuration variant, in this ninth component configurationvariant it is provided that the two clutches D and F are now positionedaxially next to one another, as an assembly with the following designfeatures:

-   -   viewed spatially, the assembly is arranged between the clutch E        and the third planetary gearset RS3;    -   a common disk carrier is provided for the clutches D and F,        which forms a section of the shaft 8 of the transmission, is        formed as the outer disk carrier D_a, F_a for the two clutches        D, F and accommodates the disk sets D_l, F_l and, in an axially        movable manner, the servomechanisms D_s, F_s provided for        actuating the disk sets D_l, F_l, so that the two        servomechanisms D_s, F_s always rotate at the speed of the shaft        8 or the carrier ST2 of the second planetary gearset RS2;

the two servomechanisms D_s, F_s are positioned axially directly next toone another and thus at least partially axially between the two disksets D_l, F_l, and are separated from one another only by an outersurface of the common outer disk carrier D_a/F_a of the clutches D, F;

when the clutch D is being engaged, the servomechanism D_s actuates itsassociated disk set D_l axially in the direction of the third planetarygearset RS3;

when the clutch F is being engaged, the servomechanism F_s actuates itsassociated disk set F_l axially in the direction of the second planetarygearset RS2;

the inner disk carrier D_i of the clutch D is connected to the carrierST3 of the third planetary gearset RS3; and

the inner disk carrier F_i of the clutch F is connected, on the side ofthe assembly opposite to the third planetary gearset RS3, to the shaft 6of the transmission, which forms a cylindrical space inside which arearranged the planetary gearset RS4, the clutch C, the planetary gearsetRS2, the clutch E and the assembly with the two clutches D, F.

Finally, FIG. 12 shows an example tenth component configuration variantfor the transmission of FIG. 1, in a simplified schematicrepresentation. Starting from the consideration that the spatialarrangement of the four planetary gearsets RS1 to RS4 relative to oneanother within the transmission housing GG can also be varied withinwide limits, a transmission according to the invention is described withreference to FIG. 12 in which the sequence of the four planetarygearsets RS1 to RS4 arranged coaxially in series one after another isdifferent from that of FIG. 1, as an example showing how those withknowledge of the field can derive other effective componentconfiguration variants from the transmission concept according to theinvention. In this context a person knowledgeable in the field can ifnecessary also apply the previously mentioned suggestions regarding thedesign and arrangement of the individual components of the transmissionin an appropriate manner to the transmission represented in simplifiedform in FIG. 12.

As can be seen in FIG. 12, compared with the transmission according toFIG. 1 the kinematic coupling of the individual elements of the fourplanetary gearsets RS1 to RS4 to one another, to the six shiftingelements a to F and to the drive input shaft AN and the drive outputshaft AB, is unchanged. In contrast to the transmission of FIG. 1, inthe tenth component configuration variant proposed here it is providedthat, as viewed in the axial direction, the four individual negativeplanetary gearsets RS1 to RS4 are arranged coaxially one after anotherin the defined sequence “RS2, RS4, RS1, RS3”, with the drive input shaftAN and the drive output shaft AB arranged coaxially with one another andthe second planetary gearset RS2 forming the gearset of the automatictransmission closest to the drive input, while the third planetarygearset RS3 forms the gearset of the automatic transmission closest tothe drive output. In another design for a transmission in which thedrive input and drive output shafts are not coaxial but axis-parallel orat an angle to one another, both the drive output and the drive input ofthe transmission can be arranged on the same side of the transmissionhousing close to the third planetary gearset RS3.

As can also be seen in FIG. 12, the two clutches C and E form anassembly with a disk carrier common to both clutches C, E for holdingthe disk sets and servomechanisms of them both. This common disk carrierforms a section of the fifth shaft 5 of the transmission and isconnected on the one hand directly to the ring gear HO2 of the secondplanetary gearset RS2 and on the other hand, via a long intermediateshaft which passes centrally through the planetary gearsets RS2, RS4 andRS1, to the sun gear SO3 of the third planetary gearset RS3. In FIG. 12,as an example, this common disk carrier forms the inner disk carrier C_ifor the clutch C and the outer disk carrier E_a for the clutch E, so thedisk set of clutch C is positioned substantially radially over the diskset of clutch E in an area axially between the second planetary gearsetRS2 and the fourth planetary gearset RS4. In this case, particularly forthe supply of pressure and lubricant it is expedient to mount theservomechanisms of the two clutches C, E (not shown in FIG. 12 for thesake of simplicity) axially movably on the disk carrier C_i/E_a commonto the two clutches C and E, so that the servomechanisms of the twoclutches C, E always rotate at the speed of the fifth shaft 5 of thetransmission. If necessary a person with knowledge of the field couldalso displace the disk set of the clutch C, for example to an arearadially over the second planetary gearset RS2. Alternatively, such aperson could if necessary also arrange the disk sets of the two clutchesC, E axially next to one another.

As can also be seen in FIG. 12, the two brakes A and B form an assemblywhich, this time, is arranged in the central area of the transmission.The brakes A and B are arranged axially next to one another onapproximately the same diameter radially above the planetary gearsetsRS1 and RS4, with the brake B—in particular its disk set—in an arearadially over the first planetary gearset RS1 and the brake A on theside of the brake B facing toward the fourth planetary gearset RS4.

As can also be seen in FIG. 12, the two clutches D and F form anassembly which, viewed spatially, is arranged in an area axially betweenthe first planetary gearset RS1 and the third planetary gearset RS3. Toobtain a structural form as compact as possible with the shortestpossible length, the disk sets of the two clutches D, F are arranged oneabove the other. In the example embodiment shown in FIG. 12, for this adisk carrier common to both clutches D, F is provided to hold the disksets and servomechanisms of the two clutches D, F. This common diskcarrier forms a section of the eighth shaft 8 of the transmission and iscorrespondingly connected to the carrier ST2 of the second planetarygearset RS2 by a long intermediate shaft which passes centrally throughthe planetary gearsets RS1, RS4 and RS2 and thus partially radiallyencloses the shaft 5. In FIG. 12, as an example this common disk carrierforms the outer disk carrier D_a for the clutch D and the inner diskcarrier F_i for the clutch F, so that the disk set of clutch F isarranged substantially radially over the disk set of clutch D.Correspondingly, the inner disk carrier D_i of the (radially inner)clutch D forms a section of the shaft 2 of the transmission and isrigidly connected to the carrier ST3 of the third planetary gearset RS3and to the drive output shaft AB, whereas the outer disk carrier F_a ofthe (radially outer) clutch F forms a section of the shaft 6 of thetransmission and is rigidly connected to the carrier ST1 of the firstplanetary gearset RS2 and to the ring gear HO 3 of the third planetarygearset RS4. Particularly for the supply of pressure and lubricant, itis expedient to mount the servomechanisms of the two clutches D, F (notshown in FIG. 12 for the sake of simplicity) axially movably on the diskcarrier D_a/F_i common to the two clutches D, F, so the servomechanismsof the two clutches D, F always rotate at the speed of the shaft 8 ofthe transmission. If necessary, a person with knowledge of the fieldcould also arrange the disk sets of the two clutches D, F axially nextto one another.

Starting from the transmission layout according to FIG. 12, two furtherexample embodiments of a 10-gear automatic transmission according to theinvention will now be described with reference to the next figures, FIG.13 and FIG. 14, both of which can be operated with the same shiftinglogic as shown in FIG. 2. Starting from the consideration that the fifthshifting element E of the transmission made as a clutch serves to fixthe second planetary gearset RS2 of the transmission when necessary,FIGS. 13 and 14 show two further possibilities for coupling the fifthshifting element E kinematically to the second planetary gearset RS2.

Thus, FIG. 13 shows a schematic representation of a second exampleembodiment of a 10-gear automatic transmission according to theinvention. Different than the transmission according to FIG. 12, in thetransmission of FIG. 13 it is provided that the clutch E is now arrangedin the force flow between the seventh shaft 7 of the transmission andthe eighth shaft 8 of the transmission. Thus, according to FIG. 13 theclutch E in its engaged condition connects the sun gear SO2 and thecarrier ST2 of the second planetary gearset RS2 to one another andthereby blocks them. The spatial arrangement of the components withinthe transmission housing GG shown in FIG. 13 is substantially identicalto FIG. 12. There are slight differences due to the omission of thecommon disk carrier C_i/E_a provided in FIG. 12. In FIG. 13 it isprovided that the disk set of the clutch E is arranged in an areaaxially between the two planetary gearsets RS2 and RS4, while the diskset of the clutch C is arranged radially over the second planetarygearset RS2.

Finally, FIG. 14 shows a schematic representation of a thirdexampleembodiment of a 10-gear automatic transmission according to theinvention. Different than the transmission of FIG. 12, in thetransmission according to FIG. 14 it is provided that the clutch E isnow positioned in the force flow between the fifth shaft 5 of thetransmission and the eighth shaft 8 of the transmission. According toFIG. 14, therefore, the clutch E in its engaged condition connects thering gear HO2 and the carrier ST2 of the second planetary gearset RS2 toone another and thereby engages them. The spatial arrangement of thecomponents within the transmission housing GG shown in FIG. 14 issubstantially identical to FIG. 12. In contrast to FIG. 12 the assemblyof the two clutches D, F this time comprises disk sets arranged axiallynext to one another and a common disk carrier, this time as an examplemade as the inner disk carrier for both clutches D, F and, as a sectionof the shaft 8, connected to the carrier ST2 of the second planetarygearset RS2.

Needless to say, a person with knowledge of the field will be able toadopt any of the previously indicated suggestions concerning the designand spatial arrangement of the components of the transmission for use inthe example embodiments of a 10-gear automatic transmission according tothe invention represented in simplified form in FIGS. 13 and 14. Such aperson will also find further suggestions for expedient possiblemodifications of the transmission concept according to the invention inthe type-defining document WO 2006/074707 A1.

INDEXES

-   1 First shaft-   2 Second shaft-   3 Third shaft-   4 Fourth shaft-   5 Fifth shaft-   6 Sixth shaft-   7 Seventh shaft-   8 Eighth shaft-   A First shifting element, first brake-   A_a Outer disk carrier of the first shifting element-   A_i Inner disk carrier of the first shifting element-   A_l Disk set of the first shifting element-   A_s Servomechanism of the first shifting element-   B Second shifting element, second brake-   B_a Outer disk carrier of the second shifting element-   B_i Inner disk carrier of the second shifting element-   B_l Disk set of the second shifting element-   B_s Servomechanism of the second shifting element-   C Third shifting element, first clutch-   C_a Outer disk carrier of the third shifting element-   C_i Inner disk carrier of the third shifting element-   C_l Disk set of the third shifting element-   C_s Servomechanism of the third shifting element-   D Fourth shifting element, second clutch-   D_a Outer disk carrier of the fourth shifting element-   D_i Inner disk carrier of the fourth shifting element-   D_l Disk set of the fourth shifting element-   D_s Servomechanism of the fourth shifting element-   E Fifth shifting element, third clutch-   E_a Outer disk carrier of the fifth shifting element-   E_i Inner disk carrier of the fifth shifting element-   E_l Disk set of the fifth shifting element-   E_s Servomechanism of the fifth shifting element-   F Sixth shifting element, fourth clutch-   F_a Outer disk carrier of the sixth shifting element-   F_i Inner disk carrier of the sixth shifting element-   F_l Disk set of the sixth shifting element-   F_s Servomechanism of the sixth shifting element-   AN Drive input shaft-   AB Drive output shaft-   GG Housing-   GN Hub fixed on the housing-   GW Housing wall-   RS1 First planetary gearset-   HO1 Ring gear of the first planetary gearset-   SO1 Sun gear of the first planetary gearset-   ST1 Carrier of the first planetary gearset-   PL1 Planetary gears of the first planetary gearset-   RS2 Second planetary gearset-   HO2 Ring gear of the second planetary gearset-   SO2 Sun gear of the second planetary gearset-   ST2 Carrier of the second planetary gearset-   PL2 Planetary gears of the second planetary gearset-   RS3 Third planetary gearset-   HO3 Ring gear of the third planetary gearset-   S03 Sun gear of the third planetary gearset-   ST3 Carrier of the third planetary gearset-   PL3 Planetary gears of the third planetary gearset-   RS4 Fourth planetary gearset-   HO4 Ring gear of the fourth planetary gearset-   SO4 Sun gear of the fourth planetary gearset-   ST4 Carrier of the fourth planetary gearset-   PL4 Planetary gears of the fourth planetary gearset-   i Transmission ratio-   φ Gear-step interval

The invention claimed is:
 1. A transmission comprising: a transmissionhousing; a drive input shaft; a drive output shaft; first, second, thirdand fourth planetary gear sets, and each of the first, the second, thethird and the fourth planetary gear sets comprising first, second andthird elements; a first interconnecting member continuouslyinterconnecting the third element of the first planetary gear set withthe first element of the second planetary gear set; a secondinterconnecting member continuously interconnecting the second elementof the second planetary gear set with the third element of the thirdplanetary gear set; a third interconnecting member continuouslyinterconnecting the first element of the third planetary gear set withthe third element of the fourth planetary gear set; and six shiftingelements each selectively engageable to interconnect at least one of thefirst, second, and third elements with at least one other of the firstelements, second elements, third elements and the transmission housing;wherein the six shifting elements are selectively engageable toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 2. Theautomatic transmission according to claim 1, wherein the first, thesecond and the third elements of the first planetary gear set comprise afirst sun gear, a first planet carrier and a first ring, the first, thesecond and the third elements of the fourth planetary gear set comprisea fourth sun gear, a fourth planet carrier and a fourth ring, and thefirst interconnecting shaft permanently connects the first sun gear ofthe first planetary gear shift gear set with the fourth sun gear of thefourth planetary gear set.
 3. The automatic transmission according toclaim 1, wherein the first, the second and the third elements of thefirst planetary gear set comprise a first sun gear, a first planetcarrier and a first ring, the first, the second and the third elementsof the third planetary gear set comprise a third sun gear, a thirdplanet carrier and a third ring, and the second interconnecting shaftpermanently connects the first planet carrier of the first planetarygear set with the third ring gear of the third planetary gear set. 4.The automatic transmission according to claim 1, wherein the first, thesecond and the third elements of the first second gear set comprise asecond sun gear, a second planet carrier and a second ring, the first,the second and the third elements of the fourth planetary gear setcomprise a fourth sun gear, a fourth planet carrier and a fourth ring,and the third interconnecting shaft permanently connects the second sungear of the second planetary gear set with the fourth ring gear of theelements of the fourth planetary gear set.
 5. The automatic transmissionaccording to claim 1, wherein the automatic transmission achieves ahill-holder function by engagement of four of the sixth shiftingelements.
 6. The automatic transmission according to claim 1, whereinengagement of one of the sixth shifting elements facilitates blocking ofthe second planetary gear set so that all three of the elements of thesecond planetary gear set rotate in unison with one another.
 7. Theautomatic transmission according to claim 1, wherein the firstinterconnecting member is connectable to the input shaft by engaging oneof the six shift elements.
 8. The automatic transmission according toclaim 1, wherein the third interconnecting shaft permanently connectsone of the elements of the second planetary gear set with one of theelements of the third planetary gear set.
 9. The automatic transmissionaccording to claim 8, wherein one of the elements of the secondplanetary gear set is permanently connected with two of the six shiftingelements.
 10. The automatic transmission according to claim 1, whereinthe first, the second and the third elements of the first planetary gearset comprise a first sun gear, a first planet carrier and a first ring,the first, the second and the third elements of the first second gearset comprise a second sun gear, a second planet carrier and a secondring, the first, the second and the third elements of the thirdplanetary gear set comprise a third sun gear, a third planet carrier anda third ring, and the first, the second and the third elements of thefourth planetary gear set comprise a fourth sun gear, a fourth planetcarrier and a fourth ring.